The present invention relates generally to cellular telephones, and more particularly to adapters that adapt a cellular telephone for use in a vehicle.
Cellular telephones are extremely popular and are being used by a larger segment of the population hand-held cellular telephones may be used by their owners either in or outside of vehicles. When the telephone is one that is normally carried by the user, an adapter is required to run the telephone off of the vehicle electrical power rather than the telephone battery. The present invention is directed to an adapter for a cellular telephone that utilizes solderless ground contacts.
The prior art describes a number of adapters that permit operation of various electronic devices from the electrical power source of a vehicle. These adapters all share certain common components. Each adapter must have a "hot" contact that is connected to the vehicle "hot" source of power, and each adapter must have a "return" or "ground" contact that is connected to the ground of the vehicle.
Some of these adapters utilize internal circuit boards and have their ground contacts connected directly to the circuit board, such as by soldering. The soldered joint may be positioned on the circuit board in an area where it undergoes great stress, inasmuch as the adapter ground contacts are typically themselves compressed when inserted into a cigarette lighter receptacle. The present invention is directed to an adapter that utilizes a solderless connection for its ground contacts, and positions the ground contacts in such a manner that any contact forces exerted by the contacts on the adapter circuit board balance each other so as not to apply any detrimental, unbalanced stress to the circuit board or other part of the adapter.
Adapters of the prior art also contain charging circuits that charge the telephone battery while connected to the vehicle. These charging circuits give off heat and may increase the temperature of the adapter to one that is uncomfortably warm to the user. The present invention overcomes this problem by utilizing a flexible, textured and insulative cover that lies over a portion of the surface of the adapter.